Mattress assembly with high airflow

ABSTRACT

Mattress assemblies that provide user comfort and increased airflow generally include multilayered foams having open celled structures. Viscoelastic foams can be utilized having intact windows between adjacent cells of less than 50 percent.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.61/513,090, filed Jul. 29, 2011, incorporated herein by reference in itsentirety.

BACKGROUND

The present disclosure generally relates to foam mattress assembliesexhibiting increased airflow.

Foam mattresses such as those formed of polyurethane foam, latex foam,and the like, are generally known in the art. One of the ongoingproblems associated with foam mattress assemblies is user comfort. Toaddress user comfort, these mattresses are often fabricated withmultiple foam layers having varying properties such as density andhardness, among others, to suit the needs of the intended user. Morerecently, manufacturers have employed so called memory foam, alsocommonly referred to as viscoelastic foams, which are generally acombination of polyurethane and one or more additives that increase foamdensity and viscosity, thereby increasing its viscoelasticity. Thesefoams are often open cell foam structures having both closed and opencells but in some instances may be reticulated foam structures. The term“reticulated” generally refers to a cellular foam structure in which thesubstantially all of the membrane windows are removed leaving a skeletalstructure. In contrast, open cell structures include both open cell(interconnected cells) and closed cells.

When used in a mattress, the memory foam conforms to the shape of a userwhen the user exerts pressure onto the foam, thereby minimizing pressurepoints from the user's body. The memory foam then returns to itsoriginal shape when the user and associated pressure are removed.However, the return to the original shape is a relatively slow processbecause of the viscoelastic cellular structure of these types of foams.

Unfortunately, the high density of foams used in current mattressassemblies, particularly those employing memory foam layers, generallyprevents proper ventilation. As a result, the foam material can exhibitan uncomfortable level of heat to the user after a period of time.Additionally, these foams can retain a high level of moisture, furthercausing discomfort to the user and potentially leading to foul odors.

Reticulated memory foams, i.e., foams in which the cellular walls aresubstantially removed, are known to provide greater airflow. However,because substantially all of the cellular walls have been removedleaving behind a skeletal structure, these foams are inherently weak,provide less load-bearing capabilities relative to other non-reticulatedviscoelastic foams, and are subject to fatigue at a rate faster thanpartially or completely closed cell foam structures. Moreover,reticulated viscoelastic foams require special processing to remove thecellular walls to form the skeletal structure making these foamsrelatively expensive.

Accordingly, it would be desirable to provide a mattress assembly,especially a mattress including one or more layers of aviscoelasticmemory foam, with an improved airflow to effectively dissipate userheat.

BRIEF SUMMARY

Disclosed herein are mattress assemblies exhibiting increased airflow.In one embodiment, a mattress assembly comprises a non-viscoelasticfirst foam layer comprising planar top and bottom surfaces; a secondfoam layer overlaying top planar surface of the first foam layer, thesecond foam layer comprising a pre-stressed foam having planar top andbottom surfaces; and a viscoelastic third foam layer overlaying the topplanar surface of the second foam layer, the second foam layercomprising planar top and bottom, wherein the viscoelastic third foamlayer is the uppermost layer of the mattress assembly.

In another embodiment, a mattress assembly, comprises a non-viscoelasticfirst foam layer having top and bottom planar surfaces; anon-viscoelastic second foam layer overlaying the top planar surface ofthe non-viscoelastic first foam layer having planar top and bottomsurfaces; a viscoelastic third foam layer overlaying the top planarsurface of the second foam layer having planar top and bottom surfaces;and a viscoelastic fourth foam layer overlaying the top planar surfaceof the third foam layer, wherein the fourth foam layer is the uppermostlayer of the mattress assembly.

In yet another embodiment, a mattress assembly comprises anon-viscoelastic first foam layer having planar top and bottom surfaces;a non-viscoelastic second foam layer overlaying the top planar surfaceof the first foam layer having planar top and bottom surfaces; aviscoelastic foam third layer overlaying the top planar surface of thesecond foam layer having planar top and bottom surfaces; and a gelinfused viscoelastic fourth foam layer overlaying the top planar surfaceof the third foam layer having equal to or less than 50 percent byweight gel loading; and a viscoelastic fifth foam layer overlaying thetop planar surface of the fourth foam layer, wherein the fifth foamlayer is the uppermost layer of the mattress assembly.

The disclosure may be understood more readily by reference to thefollowing detailed description of the various features of the disclosureand the examples included therein.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the figures wherein the like elements are numberedalike:

FIG. 1 illustrates a top down view of a mattress assembly;

FIG. 2 illustrates a cross sectional view of a mattress assembly takenalong line 1-1 of FIG. 1 in accordance with an embodiment of the presentdisclosure;

FIG. 3 illustrates a cross sectional view of a mattress assembly takenalong line 1-1 of FIG. 1 in accordance with an embodiment of the presentdisclosure;

FIG. 4 illustrates a cross sectional view of a mattress assembly takenalong line 1-1 of FIG. 1 in accordance with an embodiment of the presentdisclosure; and

FIG. 5 illustrates a cross sectional view of a mattress assembly takenalong line 1-1 of FIG. 1 in accordance with an embodiment of the presentdisclosure.

DETAILED DESCRIPTION

Disclosed herein are mattress assemblies that provide user comfort withimproved airflow to effectively dissipate user heat during use. FIG. 1illustrates a top down view representative of the various mattressassemblies, which are generally designated by reference numeral 10. Aswill be discussed herein, the various embodiments of the mattressassemblies disclosed herein have in common the following components:multiple stacked foam layers, wherein the uppermost foam layer 12 isshown, a side rail assembly 14 about at least a portion of the perimeterof the stacked mattress layers, and an optional fabric covering 16 aboutat least the side rail assembly as shown, e.g., a mattress border. Insome embodiments, the optional fabric covering may overlay the uppermostfoam layer 12 and extend about the perimeter. The uppermost foam layer12 is generally referred to herein as the cover layer and has a planartop surface adapted to substantially face the user resting on themattress assembly and having a length and width dimensions sufficient tosupport a reclining body of the user.

FIG. 2 shows a cross sectional view of a mattress assembly in accordancewith one embodiment. The mattress assembly 100 includes a base core foamlayer 102 configured with generally planar top and bottom surfaces. Forthis as well as the other embodiments disclosed herein, the core foamlayer 102 is chosen to have a thickness greater than or equal to theoverall thickness of the mattress assembly. Generally, the thickness ofthe foam core layer 102 is 4 inches to 10 inches, with about 6 inches to8 inches thickness in other embodiments, and about 6.5 inches in stillother embodiments. The core foam layer can be formed of standardpolyurethane foam although other foams can be used, including withoutlimitation, viscoelastic foams. In one embodiment, the core foam layeris open cell polyurethane foam. In other embodiments, the core foamlayer is closed cell polyurethane foam. The core foam layer 102 has adensity of 1 pound per cubic foot (lb/ft³) to 5 lb/ft³. In otherembodiments, the density is 1 lb/ft³ to 3 lb/ft³ and in still otherembodiments, from 1 lb/ft³ to 2 lb/ft³. By way of example, the densitycan be 1.65 lb/ft³. The hardness of the core foam layer, also referredto as the indention load deflection (ILD) or indention force deflection(IFD), is within a range of 20 to 40 pounds-force, wherein the hardnessis measured in accordance with ASTM D-3574 and is generally defined asthe amount of force in pounds required to indent a 50″ disc into a15″×15″×4″ foam sample and make a 1″ indentation. In one embodiment, thehardness is about 32 to 35 pounds-force.

A relatively thin pre-stressed polyurethane foam layer 104 includingplanar top and bottom surfaces is disposed on the base core foam layer102. Suitable pre-stressed polyurethane foams are generally formed inthe manner disclosed in U.S. Pat. No. 7,690,096 to Gladney et al.,incorporated herein by reference in its entirety. By way of example, aforce can applied to at least a section of a standard polyurethane foamlayer in an amount sufficient to temporarily compress its height so asto permanently alter a mechanical property of the foam layer to providea pre-stressed foam layer having a firmness that is different from thefirmness of a similar polyurethane foam that was not pre-stressed. Thepre-stressed polyurethane foam layer is a standard polyurethane foam asnoted above (i.e., not viscoelastic) and generally has a pre-stressedthickness of less than 1 inch to 0.5 inches. The density is generallyless than 2.5 lb/ft³ to 0.5 lb/ft³ in some embodiments, and less than 2lb/ft³ to 1 lb/ft³ in still other embodiments. The hardness is generallyless than 30 pounds-force to 10 pounds-force in some embodiments, andless than 25 pounds-force to 15 pounds-force in still other embodiments.In one embodiment, the thickness is 0.5 inches, the hardness is 22pounds-force, and the density is 1.5 lb/ft³.

A cover panel 106 is formed of a viscoelastic foam and disposed on thepolystyrene foam layer 104. The viscoelastic polyurethane foam in thisembodiment as well as in the other embodiments disclosed herein where aviscoelastic foam is utilized in the mattress assembly has an open cellstructure, wherein the percentage of intact windows (i.e., cell walls)between adjacent cells is less than 50 percent in one embodiment, andless than 40 percent in other embodiments, and less than 30 percent instill other embodiments. The cover panel 106 in this embodiment hasplanar top and bottom surfaces. The thickness is generally less than 3inches to 0.5 inches in some embodiments, and less than 2 inches to 1inch in other embodiments. The density is less than 3 lb/ft³ to 1 lb/ft³in some embodiments, and less than 2.5 lb/ft³ to 2 lb/ft³ in otherembodiments. In one embodiment, the hardness is generally less than 15pounds-force to 5 pounds-force. In one embodiment, the cover panel is ata thickness of 1.5″, a density of 2.5 lb/ft³, and a hardness is 12pounds-force.

The various multiple stacked mattress layers 102, 104, and 106 may beadjoined to one another using an adhesive or may be thermally bonded toone another or may be mechanically fastened to one another.

The mattress assembly further includes a foam side rail assembly 120about all or a portion of the perimeter of the mattress layers 102, 104,106. The side rails that define the assembly may be attached or placedadjacent to at least a portion of the perimeter of the mattress layers102, 104, 106, and may include metal springs, spring coils, encasedspring coils, foam, latex, gel, viscoelastic gel, or a combination, inone or more layers. Side rails may be placed on opposing sides of thestacked mattress layers, on all four sides of the stacked mattresslayers, or only on one side of the stacked mattress layers. In certainembodiments, the side rails may comprise edge supports with firmnessgreater than that provided by the stacked mattress layers. The siderails may be fastened to the stacked mattress layers via adhesives,thermal bonding, or mechanical fasteners.

In one embodiment, the side rail assembly is formed of a polyurethanefoam having a density generally less than 3 lb/ft³ and a hardnessgreater than 30 pounds-force. In one embodiment, the side rails areformed of having a density of 1.65 lb/ft³ and a hardness of 45pounds-force.

In another embodiment, the side rail assembly 120 is formed of open cellpolyurethane foam having a non-random large cell structure or a randomcellular structure with many large cells. The large cell structure canbe defined by the number of cells per linear inch. In one embodiment,the large cell structure is about 10 to 40 cells per inch, with about 15to 30 cells per inch in other embodiments, and with about 20 cells perinch in still other embodiments. The open cell foam structure includes aplurality of interconnected cells, wherein the windows between theadjacent cells are broken and/or removed. In contrast, in a closed cellfoam there are substantially no interconnected cells and the windowsbetween the adjacent cells are substantially intact. In reticulatedfoams, substantially all of the windows are removed. By using an opencell structure with a large open cellular structure, movement ofmoisture and air through a side rail can occur. Also, if the side railis adhesively or thermally attached to the mattress layers, e.g., 102,104, and 106, the skeletal struts of the open cell foam will bond to themattress layers, thereby facilitating air and moisture transfer from themattress layers through the side layers to the environment. In oneembodiment, the side rail assembly includes a reticulated viscoelasticpolyurethane foam.

For ease in manufacturing the mattress assembly, the side rail assemblymay be assembled in linear sections that are joined to one another toform the perimeter about the mattress layers. The ends may be square asshown in the top down view FIG. 1 or may be mitered.

An optional fabric layer 122 is disposed about the perimeter of the siderail, i.e., serves as a mattress border. The fabric border layer isattached at one end to the top planar surface of the uppermost mattresslayer 106 and at the other end to the bottom planar surface of thebottom most layer 102. In one embodiment, at least a portion of thefabric layer is formed of a spacer fabric to provide a further increasein airflow. As used herein, spacer fabrics are generally defined as pilefabrics that have not been cut including at least two layers of fabricknitted independently that are interconnected by a separate spacer yarn.The spacer fabrics generally provide increased breathability relative toother fabrics, crush resistance, and a three dimensional appearance. Theat least two fabric layers may be the same or different, i.e., the sameor different density, mesh, materials, and like depending on theintended application. When employing the spacer fabric, a lightweightflame retardant barrier layer may be disposed intermediate to themattress foam layers and the spacer fabric about the perimeter of theside rail assembly.

In the embodiment shown, the mattress assembly 100 is generally lessthan 12 inches in height. By way of example, an exemplary mattressassembly illustrative of the embodiment shown in FIG. 2 has a 6.5″ foamcore layer of standard polyurethane foam having a density of 1.65 lb/ft³and a hardness of about 32-35 pounds-force ILD; a 0.5″ pre-stressedpolyurethane foam intermediate layer; and 1.5″ top cover layer ofviscoelastic polyurethane foam having a density of 2.5 lb/ft³ and ahardness of about 12 pounds-force. The side rail assembly may have athickness of 2″ and is formed of an open cell foam having about 20 cellsper linear inch as described above. A mattress border and panel of aspacer fabric is utilized as a mattress border.

FIG. 3 shows a cross sectional view of a mattress assembly in accordancewith one embodiment. The mattress assembly 200 includes a base core foamlayer 202 configured with planar top and bottom surfaces. Generally, thethickness of the foam core layer 202 is 4 inches to 10 inches, withabout 6 inches to 8 inches thickness in other embodiments, and about 6.5inches in still other embodiments. The core foam layer can be formed ofstandard polyurethane foam although other foams can be used, includingwithout limitation, viscoelastic foams. In one embodiment, the core foamlayer is an open cell polyurethane foam. In other embodiments, the corefoam layer is closed cell polyurethane foam. The core foam layer 202 hasa density of 1 lb/ft³ to 5 lb/ft³. In other embodiments, the density is1 lb/ft³ to 3 lb/ft³ and in still other embodiments, from 1 lb/ft³ to 2lb/ft³. By way of example, the density can be 1.65 lb/ft³. The hardnessof the core foam layer is within a range of 20 to 40 pounds-force. Inone embodiment, the hardness is about 24 pounds-force.

A transition support layer 203 having planar top and bottom surfaces andformed of standard polyurethane foam is disposed on the base core foamlayer 202. The transition support layer 203 generally has a thicknessless than 1 inch to 0.5 inch, a density of less than 4 to 1 lb/ft³, anda hardness less than 15 to 10 pounds-force. In one embodiment, thetransition layer 203 has a thickness of 0.5″, a density of 3 lb/ft³, anda hardness of 12 pounds-force.

Viscoelastic polyurethane foam layer 205 having planar top and bottomsurfaces overlays on the transition support layer 203. The viscoelasticfoam layer 205 is generally characterized as having a thickness lessthan 1 inch, a density of less than 3 to 1 lb/ft³, and a hardness lessthan 15 to 10 pounds-force. In one embodiment, the viscoelastic foamlayer 205 has a thickness of 1″, a density of about 2.5 lb/ft³, and ahardness of 12 pounds-force.

A cover panel 206 formed of a viscoelastic foam is disposed on theviscoelastic foam layer 205. The cover panel 206 has planar top andbottom surfaces, a density of 1 to 3.5 lb/ft³, a hardness of 10 to 15pounds-force, and a thickness of 1 to 2 inches. In one embodiment, thecover panel has a thickness of 1.5″, a density of about 2.5 lb/ft³, anda hardness of about 12 pounds-force.

The mattress assembly may further include the side rail assembly 220 andthe optional fabric border 222 as described above.

By way of example, an exemplary mattress assembly illustrative of theembodiment shown in FIG. 3 has a 6.5″ foam core layer of standardpolyurethane foam having a density of 1.65 lb/ft³ and a hardness ofabout 24 pounds-force ILD; a 0.5″ transition support having a density of3 lb/ft³ and a hardness of 12 pounds-force; a 1″ viscoelasticpolyurethane foam layer having a density of 2.5 lb/ft³ and a hardness ofabout 12 pounds-force; and a cover panel layer has a thickness of 1.5″,a density of about 2.5 lb/ft³, and a hardness of about 12 pounds-force.The side rail assembly may have a thickness of 2″ and is formed of anopen cell foam having about 20 cells per linear inch as previouslydescribed. A mattress border and panel of a spacer fabric is utilized asa mattress border.

FIG. 4. shows a cross sectional view of a mattress assembly inaccordance with one embodiment. The mattress assembly 300 includes abase core foam layer 302 configured with planar top and bottom surfaces.Generally, the thickness of the foam core layer 302 is 4 inches to 10inches, with about 6 inches to 8 inches thickness in other embodiments,and about 6.5 inches in still other embodiments. The core foam layer 302can be formed of standard polyurethane foam although other foams can beused, including without limitation, viscoelastic foams. In oneembodiment, the core foam layer is an open cell polyurethane foam. Inother embodiments, the core foam layer is closed cell polyurethane foam.The core foam layer 302 has a density of 1 pound per square foot(lb/ft³) to 5 lb/ft³. In other embodiments, the density is 1 lb/ft³ to 3lb/ft³ and in still other embodiments, from 1 lb/ft³ to 2 lb/ft³. By wayof example, the density can be 1.65 lb/ft³. The hardness of the corefoam layer is within a range of 20 to 40 pounds-force. In oneembodiment, the hardness is about 24 pounds-force.

A transition support layer 303 having planar top and bottom surfaces andformed of standard polyurethane foam is disposed on the base core foamlayer 302. The transition support layer 303 generally has a thickness of0.5 to 1 inch, a density of 1 to 4 lb/ft³, and a hardness of 10 to 15pounds-force. In one embodiment, the transition layer 303 has athickness of 0.5″, a density of 3 lb/ft³, and a hardness of 12pounds-force.

Viscoelastic polyurethane foam layer 305 having planar top and bottomsurfaces is disposed on the transition support layer 303. Theviscoelastic foam layer 305 is generally characterized as having athickness of 1 to 3 inches, a density of 1 to 4 lb/ft³, and a hardnessof 10 to 15 pounds-force. In one embodiment, the viscoelasticpolyurethane foam layer 305 has a thickness of 1.5″, a density of about2.5 lb/ft³, and a hardness of 12 pounds-force.

A gel infused viscoelastic foam layer 307 having planar top and bottomsurfaces is disposed on the viscoelastic foam layer 305. Suitable gelinfused viscoelastic layers are generally disclosed in US Pat. No.2010/0005595 to Gladney et al., which is incorporated by reference inits entirety. In one embodiment, the gel infused viscoelastic foam layeris infused with gel at less than about 50 percent by weight in someembodiments, with less than 40 percent by weight in other embodiments,and with less than 35 percent in still other embodiments. Optionally,the gel infused viscoelastic layer may be loaded with activated carbonfor odor control. In one embodiment, the gel infused visco elastic foamlayer 307 is formed of a non-random open cell polyurethane viscoelasticfoam having a thickness of 0.5 to 2 inches, a density of 3 to 6 lb/ft³and a hardness of 10 to 15 pounds-force. In one embodiment, the gelinfused viscoelastic foam layer 307 has a 36 percent by weight gelloading, a density of 4.5 lb/.ft³, and a hardness of 11 pounds-force.

A cover panel 306 formed of a viscoelastic foam is disposed on the gelinfused viscoelastic foam layer 307. The cover panel 306 has planar topand bottom surfaces, a density of 1 to 3.5 lb/ft³, a hardness of 10 to15 pounds-force, and a thickness of 0.5 to 2 inches. In one embodiment,the cover panel has a thickness of 1.5″, a density of about 2.5 lb/ft³,and a hardness of about 11 pounds-force.

The mattress assembly may further include the side rail assembly 320 andthe optional fabric border 322 as described above.

By way of example, an exemplary mattress assembly illustrative of theembodiment shown in FIG. 3 has a 6.5″ foam core layer of standardpolyurethane foam having a density of 1.65 lb/ft³ and a hardness ofabout 24 pounds-force ILD; a 0.5″ transition support having a density of3 lb/ft³ and a hardness of 12 pounds-force; a 1.5″ viscoelasticpolyurethane foam layer having a density of 2.5 lb/ft³ and a hardness ofabout 12 pounds-force; a 1″ gel infused viscoelastic foam layer having a36 percent by weight gel loading, a density of 4.5 lb/.ft³, and ahardness of 11 pounds-force; and a cover panel layer having a thicknessof 1.5″, a density of about 2.5 lb/ft³, and a hardness of about 11pounds-force. The side rail assembly may have a thickness of 2″ and isformed of an open cell foam having about 20 cells per linear inch aspreviously described. A mattress border and panel of a spacer fabric isutilized as a mattress border.

FIG. 5 shows a cross sectional view of a mattress assembly in accordancewith one embodiment. The mattress assembly 400 includes a base core foamlayer 402 configured with planar top and bottom surfaces. Generally, thethickness of the foam core layer 402 is 4 inches to 10 inches, withabout 6 inches to 8 inches thickness in other embodiments, and about 6.5inches in still other embodiments. The core foam layer 402 can be formedof standard polyurethane foam although other foams can be used,including without limitation, viscoelastic foams. In one embodiment, thecore foam layer is an open cell polyurethane foam. In other embodiments,the core foam layer is closed cell polyurethane foam. The core foamlayer 302 has a density of 1 pound per square foot (lb/ft³) to 5 lb/ft³.In other embodiments, the density is 1 lb/ft³ to 3 lb/ft³ and in stillother embodiments, from 1 lb/ft³ to 2 lb/ft³. The hardness is within arange of 20 to 40 pounds-force. By way of example, the core layer 402can have a thickness of 8″, a density of 1.65 lb/ft³ and a hardness of24 pounds-force.

A transition support layer 403 having planar top and bottom surfaces andformed of standard polyurethane foam is provided on the base core foamlayer 402. The transition support layer 403 generally has a thicknessless than 1″, a density of less than 4 lb/ft³, and a hardness less than15 pounds-force. In one embodiment, the transition layer 403 has athickness of 0.5″, a density of 3 lb/ft³, and a hardness of 12pounds-force.

Viscoelastic polyurethane foam layer 405 having planar top and bottomsurfaces is disposed on the transition support layer 403. Theviscoelastic foam layer 405 is generally characterized as having athickness less than 3 inches, a density of less than 4.5 lb/ft³, and ahardness less than 15 pounds-force. In one embodiment, the viscoelasticpolyurethane foam layer 405 has a thickness of 1.5″, a density of about3.5 lb/ft³, and a hardness of 11 pounds-force.

A gel infused viscoelastic foam layer 407 having planar top and bottomsurfaces is disposed on the viscoelastic foam layer 405. In oneembodiment, the gel infused viscoelastic foam layer is infused with gelat less than about 50 percent by weight in some embodiments, with lessthan 40 percent by weight in other embodiments, and with less than 35percent in still other embodiments. Optionally, the gel infusedviscoelastic layer may be loaded with activated carbon for odor control.In one embodiment, the gel infused visco elastic foam layer 407 isformed of a non-random open cell polyurethane viscoelastic foam having athickness less than 2 inches, a density generally less than 6 lb/ft³ anda hardness greater than 15 pounds-force. In one embodiment, the gelinfused viscoelastic foam layer 407 has a 36 percent by weight gelloading, a density of 4.5 lb/.ft³, and a hardness of 11 pounds-force.

A cover panel 406 formed of a viscoelastic foam is disposed on the gelinfused viscoelastic foam layer 407. The cover panel 406 has planar topsurface and a convoluted bottom surface, a density less than 4.5 lb/ft³,a hardness less than 15 pounds-force, and a thickness less than 2″. Theconvoluted bottom surface is in contact with the top planar surface ofthe gel infused viscoelastic layer 307. An exemplary convoluted foam hasan egg crate structure such as the one disclosed in US Pat. Pub. No.2007/0226911 to Gladney et al., incorporated herein by reference in itsentirety. In one embodiment, the cover panel has a thickness of 1.5″, adensity of about 3.5 lb/ft³, and a hardness of about 11 pounds-force.

The mattress assembly may further include the side rail assembly 420 andthe optional fabric border 422 as described above.

By way of example, an exemplary mattress assembly illustrative of theembodiment shown in FIG. 4 has a 8″ foam core layer of standardpolyurethane foam having a density of 1.65 lb/ft³ and a hardness ofabout 24 pounds-force ILD; a 0.5″ transition support having a density of3 lb/ft³ and a hardness of 12 pounds-force; a 1.5″ viscoelasticpolyurethane foam layer having a density of 3.5 lb/ft³ and a hardness ofabout 11 pounds-force; a 1.5″ gel infused viscoelastic foam layer havinga 36 percent by weight gel loading, a density of 4.5 lb/.ft³, and ahardness of 11 pounds-force; and a cover panel layer having a convolutedbottom surface, a thickness of 1.5″, a density of about 3.5 lb/ft³, anda hardness of about 11 pounds-force. The side rail assembly may have athickness of 2″ and is formed of an open cell foam having about 20 cellsper linear inch as previously described. A mattress border and panel ofa spacer fabric is utilized as a mattress border.

The various mattress layers in the mattress assemblies described abovemay be adjoined to one another using an adhesive or may be thermallybonded to one another or may be mechanically fastened to one another.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to make and use the invention. The patentable scope of the inventionis defined by the claims, and may include other examples that occur tothose skilled in the art. Such other examples are intended to be withinthe scope of the claims if they have structural elements that do notdiffer from the literal language of the claims, or if they includeequivalent structural elements with insubstantial differences from theliteral languages of the claims.

1. A mattress assembly, comprising: a non-viscoelastic first foam layer comprising planar top and bottom surfaces; a second foam layer overlaying top planar surface of the first foam layer, the second foam layer comprising a pre-stressed foam having planar top and bottom surfaces; and a viscoelastic third foam layer overlaying the top planar surface of the second foam layer, the second foam layer comprising planar top and bottom, wherein the viscoelastic third foam layer is the uppermost layer of the mattress assembly.
 2. The mattress assembly of claim 1, wherein the viscoelastic third foam layer has intact windows between adjacent cells of less than 50 percent.
 3. The mattress assembly of claim 1, wherein the non-viscoelastic first foam layer is an open celled polyurethane foam.
 4. The mattress assembly of claim 1, wherein the non-viscoelastic first foam layer has a thickness of 4 to 10 inches, a hardness of 20 to 40 pounds-force, and a density of 1 to 5 lb/ft³; the second pre-stressed foam layer has a thickness of 0.5 to 1 inch, a hardness of 10 to 30 pounds-force, and a density of 0.5 to 2.5 lb/ft³; and the viscoelastic third foam layer has a thickness of 0.5 to 3 inches, a hardness of 5 to 15 pounds-force, and a density of 1 to 3 lb/ft³.
 5. The mattress assembly of claim 1, wherein the non-viscoelastic first foam layer has a thickness of 6.5 inches, a hardness of 32-35 pounds-force, and a density of 1.65 lb/ft³; the second pre-stressed foam layer has a thickness of 1.5 inches, a hardness of 22 pounds-force, and a density of 1.5 lb/ft³; and the viscoelastic third foam layer has a thickness of 1 to 2 inches, a hardness of 12 pounds-force, and a density of 2.5 lb/ft³.
 6. The mattress assembly of claim 1, further comprising a side rail assembly formed of open cell polyurethane foam.
 7. The mattress assembly of claim 1, further comprising a fabric layer about a perimeter to the mattress assembly, wherein at least a portion of the fabric layer is formed of a spacer fabric.
 8. A mattress assembly, comprising: a non-viscoelastic first foam layer having top and bottom planar surfaces; a non-viscoelastic second foam layer overlaying the top planar surface of the non-viscoelastic first foam layer having planar top and bottom surfaces; a viscoelastic third foam layer overlaying the top planar surface of the second foam layer having planar top and bottom surfaces; and a viscoelastic fourth foam layer overlaying the top planar surface of the third foam layer, wherein the fourth foam layer is the uppermost layer of the mattress assembly.
 9. The mattress assembly of claim 8, wherein the viscoelastic third and fourth foam layer have intact windows between adjacent cells of less than 50 percent.
 10. The mattress assembly of claim 8, wherein the non-viscoelastic first and second foam layers are an open celled polyurethane foam.
 11. The mattress assembly of claim 8, wherein the non-viscoelastic first foam layer has a thickness of 4 to 10 inches, a hardness of 20 to 40 pounds-force, and a density of 1 to 5 lb/ft³; the non-viscoelastic second foam layer has a thickness of 0.5 to 1 inch, a hardness of 10 to 15 pounds-force, and a density of 1 to 4 lb/ft³; the viscoelastic third foam layer has a thickness of 0.5 to 1 inches, a hardness of 10 to 15 pounds-force, and a density of 1 to 3 lb/ft³; and the viscoelastic fourth layer has a thickness of 0.5 to 2 inches, a hardness of 10 to 15 pounds-force, and a density of 1 to 3.5 lb/ft³.
 12. The mattress assembly of claim 8, wherein the non-viscoelastic first foam layer has a thickness of 6.5 inches, a hardness of 24 pounds-force, and a density of 1.65 lb/ft³; the non-viscoelastic second foam layer has a thickness of 1 inch, a hardness of 12 pounds-force, and a density of 3 lb/ft³; the viscoelastic third foam layer has a thickness of 1 inch, a hardness of 12 pounds-force, and a density of 2.5 lb/ft³; and the viscoelastic fourth layer has a thickness of 1.5 inches, a hardness of 12 pounds-force, and a density of 2.5 lb/ft³.
 13. The mattress assembly of claim 8, further comprising a side rail assembly formed of open cell polyurethane foam.
 14. The mattress assembly of claim 8, further comprising a fabric layer about a perimeter to the mattress assembly, wherein at least a portion of the fabric layer is formed of a spacer fabric.
 15. A mattress assembly, comprising: a non-viscoelastic first foam layer having planar top and bottom surfaces; a non-viscoelastic second foam layer overlaying the top planar surface of the first foam layer having planar top and bottom surfaces; a viscoelastic foam third layer overlaying the top planar surface of the second foam layer having planar top and bottom surfaces; and a gel infused viscoelastic fourth foam layer overlaying the top planar surface of the third foam layer having equal to or less than 50 percent by weight gel loading; and a viscoelastic fifth foam layer overlaying the top planar surface of the fourth foam layer, wherein the fifth foam layer is the uppermost layer of the mattress assembly.
 16. The mattress assembly of claim 15, wherein the viscoelastic third, fourth and fifth foam layers have intact windows between adjacent cells of less than 50 percent.
 17. The mattress assembly of claim 15, wherein the non-viscoelastic first and second foam layers are an open celled polyurethane foam.
 18. The mattress assembly of claim 15, wherein the non-viscoelastic first foam layer has a thickness of 4 to 10 inches, a hardness of 20 to 40 pounds-force, and a density of 1 to 5 lb/ft³; the non-viscoelastic second foam layer has a thickness of 0.5 to 1 inch, a hardness of 10 to 15 pounds-force, and a density of 1 to 4 lb/ft³; the viscoelastic third foam layer has a thickness of 1 to 3 inches, a hardness of 10 to 15 pounds-force, and a density of 1 to 4 lb/ft³; the gel infused viscoelastic fourth foam layer has a thickness of 1 to 2 inches, a hardness of 10 to 15 pounds-force, and a density of 3 to 6 lb/ft³; and the viscoelastic fifth layer has a thickness of 0.5 to 2 inches, a hardness of 10 to 15 pounds-force, and a density of 1 to 3.5 lb/ft³.
 19. The mattress assembly of claim 15, wherein the non-viscoelastic first foam layer has a thickness of 6.5 inches, a hardness of 24 pounds-force, and a density of 1.65 lb/ft³; the non-viscoelastic second foam layer has a thickness of 0.5 inch, a hardness of 12 pounds-force, and a density of 3 lb/ft³; the viscoelastic third foam layer has a thickness of 1.5 inches, a hardness of 12 pounds-force, and a density of 2.5 lb/ft³; the gel infused viscoelastic fourth foam layer has a thickness of 1 inch, a hardness of 11 pounds-force, and a density of 4.5 lb/ft³; and the viscoelastic fifth layer has a thickness of 1.5 inches, a hardness of 11 pounds-force, and a density of 2.5 lb/ft³.
 20. The mattress assembly of claim 15, further comprising a side rail assembly formed of open cell polyurethane foam.
 21. The mattress assembly of claim 15, further comprising a fabric layer about a perimeter to the mattress assembly, wherein at least a portion of the fabric layer is formed of a spacer fabric.
 22. The mattress assembly of claim 15, wherein the gel infused viscoelastic fourth foam layer further comprises activated carbon.
 23. The mattress assembly of claim 15, wherein the non-viscoelastic first foam layer has a thickness of 8 inches, a hardness of 24 pounds-force, and a density of 1.65 lb/ft³; the non-viscoelastic second foam layer has a thickness of 0.5 inch, a hardness of 12 pounds-force, and a density of 3 lb/ft³; the viscoelastic third foam layer has a thickness of 1.5 inches, a hardness of 12 pounds-force, and a density of 3.5 lb/ft³; the gel infused viscoelastic fourth foam layer has a thickness of 1.5 inches, a hardness of 11 pounds-force, and a density of 4.5 lb/ft³; and the viscoelastic fifth layer has a thickness of 1.5 inches, a hardness of 11 pounds-force, and a density of 3.5 lb/ft³. 